Why is there a black border around my artboard when saved to a press quality pdf in Illustrator CC?

[jillo10791090]

I created a brochure in Illy CC and when saving it as a press quality pdf with printers marks and bleeds, it shows a black line where the artboard edge is.  My printer alerted me to the problem and I found if I hide the artboards in ai file and save the same way as press quality pdf it works.  I've never had to hide artboards in CS5 when saving from ai file to pdf. Does anyone know the reason for this or have suggestions other than hiding the artboards before I save as pdf?

[Monika Gause]

In which app do you open the PDF?

Some apps show the PDF boxes.

Can you check if there is really an object with a stroke?

[jillo10791090]

Thanks, Monika. Printer is using Acrobat Pro, do you know if that app shows a border on artboards? But, I've worked with this printer before when using CS5 and didn't need to hide artboards.   And, yes, I checked all the objects.  Once the artboards were hidden, voila!

[Monika Gause]

Can you create  a test document that shows the error and upload it to Dropbox or the like?